1. Field of the Invention
The present invention is generally related to communication connectors and their components, including telecommunications connectors.
2. Description of the Related Art
Conductors that are not physically connected to one another may nonetheless be coupled together electrically and/or magnetically. This creates an undesirable signal in the adjacent conductor referred to as crosstalk.
By placing two elongated conductors (e.g., wires) alongside each other in close proximity, a common axis can be approximated. If the opposing currents in the conductors are equal, the magnetic field ‘leakage’ from the conductors will decrease rapidly as the longitudinal distance along the conductors is increased. If the voltages are also opposite and equal, the electric field that is primarily concentrated between the conductors will also decrease as the longitudinal distance along the conductors is increased. This compact pair arrangement is often sufficient to avoid crosstalk if other similar pairs of conductors are in close proximity to the first pair of conductors. Twisting the pairs of conductors will tend to negate the residual field couplings and allow closer spacing of adjacent pairs. However, if for some reason the conductors within a pair are spaced far enough apart, undesired coupling and crosstalk may occur.
The structure of many conventional communication connectors is governed by standards including the RJ-45 type connector by FCC part 68 and the TIA/EIA 568 standards. Conventional telecommunications connectors typically include a communication plug and a communication jack configured to receive the plug. The jack typically provides an access point to a network, a communications device, and the like. Each of the plug and jack include a plurality of conductors or contacts. When the plug is received inside the jack, the contacts of the plug engage the corresponding tines of the jack.
The communication plug is typically physically connected to one end of a communication cable. The communication cable may be a 4-pair flexible cord, and the communication plug may be coupled thereto to create a patch cord. The cable (e.g., a patch cord) allows a communications device to communicate with the network, device, and the like connected to the jack. A convention for communication cables includes four twisted-wire pairs (also known as “twisted pairs”), which are each physically connected to the communication plug. Following this convention, a communication plug has eight contacts (P-T1 to P-T8) each connected to a different wire of the four twisted pairs (referred to as “twisted pair 1,” “twisted pair 2,” “twisted pair 3,” and “twisted pair 4” herein). Each twisted pair serves as a differential signaling pair wherein signals are transmitted thereupon and expressed as voltage and current differences between the wires of the twisted pair. A twisted pair can be susceptible to electromagnetic sources including another nearby cable of similar construction. Signals received by the twisted pair from such electromagnetic sources external to the cable's jacket are referred to as “alien crosstalk.” The twisted pair can also receive signals from one or more wires of the three other twisted pairs within the cable's jacket, which is referred to as “local crosstalk” or “internal crosstalk.”
The wires of the twisted pairs 1-4 are connected to the plug contacts P-T1 to P-T8 to form four differential signaling pairs: a first plug pair 1, a second plug pair 2, a third plug pair 3, and a fourth plug pair 4. The twisted pair 2 is connected to the plug pair 2, which includes the adjacent plug contacts P-T1 and P-T2. The twisted pair 4 is connected to the plug pair 4, which includes the adjacent plug contacts P-T7 and P-T8. The twisted pair 1 is connected to the plug pair 1, which includes the adjacent plug contacts P-T4 and P-T5. The twisted pair 3 is connected to the troublesome “split” plug pair 3, which includes the plug contacts P-T3 and P-T6. The plug contacts P-T3 and P-T6 flank the plug contacts P-T4 and P-T5 of the plug pair 1. The plug pairs 2 and 4 are located furthest apart from one another and the plug pairs 1 and 3 are positioned between the plug pairs 2 and 4.
A challenge of the structural requisites of conventional communication cabling standards relates to the fact that the two wires of twisted pair 3 are connected to widely spaced contacts P-T3 and P-T6 of the communication plug which straddle contacts P-T4 and P-T5 to which two wires of the twisted pair 1 are connected, while the wires of the twisted pair 2 are connected to contacts P-T1 and P-T2 and the wires of the twisted pair 4 are connected to contacts P-T7 and P-T8. This places the twisted pair 2 and the twisted pair 4 on either side of the twisted pair 3. This arrangement can cause the signal transmitted on twisted pair 3 to impart different voltages and/or currents onto twisted pair 2 and twisted pair 4 effectively causing differential voltages between the composite of both wires of twisted pair 2 and the composite of both wires of the twisted pair 4 as an undesired cable mode conversion coupling that unfortunately may enhance alien crosstalk elsewhere that is referred to hereafter as a “modal launch” or “mode conversion.”
Within the communication jack of the communication connector, the jack tines are positioned in an arrangement corresponding to the arrangement of the plug contacts P-T1 to P-T8 in the conventional communication plug. Likewise, the conventional communication cabling standards establish four differential signaling pairs: jack tine pair 2, which includes adjacent communication jack tines J-T1 and J-T2; jack tine pair 4, which includes adjacent communication jack tines J-T7 and J-T8, jack tine pair 1, which includes adjacent communication jack tines J-T4 and J-T5; and a troublesome “split” jack tine pair 3, which includes communication jack tines J-T3 and J-T6. The jack tines J-T3 and J-T6 of the jack tine pair 3 flank the jack tines J-T4 and J-T5 of the jack tine pair 1. Further, the jack tine pairs 2 and 4 are located furthest apart from one another and the jack tine pairs 1 and 3 are positioned between the jack tine pairs 2 and 4.
The “split” jack tine pair 3, with the relatively wide spacing of its jack tine J-T3 with respect to its jack tine J-T6, is especially problematic.
For illustrative purposes, the differential signal carried by the wires and associated fields of the twisted pair 3 through a conventional communication connector will now be described. First, the differential signal is associated with the wires of the twisted pair 3 into the communication plug. Within the communication plug, the wires of the twisted pair 3 are untwisted and spaced apart to connect to the split plug contacts P-T3 and P-T6. The differential signal is conducted by the split plug pair 3 to the split jack tines J-T3 and J-T6. Within the communication jack, the jack tines J-T3 and J-T6 extend inwardly toward one another to place themselves in close proximity to one another. Conductors (e.g., wires) may be connected to the jack tines J-T1 to J-T8 to carry the signal from the communication jack to a destination (e.g., a network, a device, a cable, and the like). The wires connected to the jack tines J-T3 and J-T6 of the jack tine pair 3 may be twisted together to form a twisted pair to further reduce unwanted crosstalk.
In the conventional communication connector, the mode of coupling of present concern is where the wires of twisted pair 3 are split apart within the plug (as the positions of P-T3 and P-T6 are approached) and/or the jack (J-T3 and J-T6). This splitting of wires of twisted pair 3 creates selective capacitive coupling from the two opposing signals on twisted pair 3 and increases the aperture defined by the area between the wires of pair 3 thus causing an increase of magnetic coupling between twisted pair 3 and the composite sets of wires comprising twisted pair 2 and twisted pair 4 where twisted pair 2 is treated as a two-stranded or “composite” wire as is twisted pair 4. As a result, a small “coupled” portion of the differential signal originating on twisted pair 3 appears as two opposite common, or “even,” mode signals on the two-wire composites of twisted pair 2 and twisted pair 4.
Thus, where the two-wire composites of twisted pair 2 and twisted pair 4 are treated equally, the signal transmitted on twisted pair 3 may impart opposite voltages and/or currents onto twisted pair 2 and twisted pair 4, respectively, which causes differential voltages between the composite of the two wires of twisted pair 2 and the composite of the two wires of twisted pair 4. This is the coupling, and thus a “launch,” of an undesired cable mode conversion that may increase undesired alien crosstalk elsewhere along the transmission path comprised of the plug, the jack and their respective cables.
This transmission path of the plug, the jack and their respective cables can thus be viewed as comprised of a plug in which some of the conductors are located in close proximity to one another and others are spaced farther apart, the interface between a portion of the plug and a portion of the jack and typically the site of origin of undesired mode conversion coupling, and the jack wherein conductors are located in close proximity to one another. This conventional arrangement of the transmission path may cause a “modal launch” that extends from the communication connector into the communication cable connected to the plug and/or the destination connected to the jack.
Within the communication jack, the modal launch effectively treats the jack tine pair 2 (i.e., jack tines J-T1 and J-T2) as a single two-stranded “paired” conductor PC-J1 that is distantly juxtaposed with the jack tine pair 4 (i.e., jack tines J-T7 and J-T8) as its opposite single two-stranded “paired” conductor PC-J2. In other words, the jack tines J-T1 and J-T2 of the jack tine pair 2 combine to form the first single “paired” conductor PC-J1 and the jack tines J-T7 and J-T8 connected to the jack tine pair 4 combine to form the second single “paired” conductor PC-J2. As a result, a “composite” differential pair is created inside the communication jack by the wider spaced apart first and second ‘paired’ conductors PC-J1 and PC-J2. The wider spacing of first and second ‘paired’ conductors PC-J1 and PC-J2 will unfortunately enhance vulnerability and sourcing of unwanted crosstalk among other cables situated in the vicinity, such as in a same cable tray, conduit, etc.
As noted, within the communication plug, the modal launch effectively treats the twisted pair 2 as a single two-stranded “paired” conductor PC-P1 that is distantly juxtaposed with the twisted pair 4 as its opposite single two-stranded “paired” conductor PC-P2. Again, the wires of the twisted pair 2 combine to form the first single “paired” conductor PC-P1 and the wires of the twisted pair 4 combine to form the second single “paired” conductor PC-P2. As a result, a “composite” differential pair is created in a communication cable by the wider spaced apart first and second ‘paired’ conductors PC-P1 and PC-P2. The wider spacing of the first and second ‘paired’ conductors PC-P1 and PC-P2 will unfortunately enhance vulnerability and sourcing of unwanted crosstalk among other cables situated in the vicinity, such as in a same cable tray, conduit, etc.
Within the plug-jack interface, the typical site of origin of undesired mode conversion coupling, of the communication connector, where the conductors (e.g., the wires of the twisted pair 3, the plug contacts P-T3 and P-T6, and the jack tines J-T3 and J-T6) are spaced apart from one another, the spaced apart conductors may couple (capacitively and/or inductively) with the other conductors of the communication connector. For example, within this plug-jack interface portion of the communication jack, the jack tine J-T3 is adjacent the first paired conductor PC-J1 and the jack tine J-T6 is adjacent the second paired conductor PC-J2. In the plug-jack interface portion of the communication jack, the jack tine J-T3 is capacitively coupled to the first paired conductor PC-J1 and the jack tine J-T6 is capacitively coupled to the second paired conductor PC-J2. A magnetic field forms between the split jack tines J-T3 and J-T6 that induces inductive coupling between split tines and the first and second paired conductors PC-J1 and PC-J2. Within the plug-jack interface portion of the communication plug, a similar result occurs.
A conventional approach to addressing this capacitive and inductive coupling is to cross the split conductors in the plug-jack interface, ideally at a location near a midpoint of the plug-jack interface from which mode conversion coupling occurs. For example, the split conductors may be crossed within the communication jack, the communication plug, or both.
If the split conductors are crossed inside the communication jack, a first portion of the jack tine J-T3 is adjacent the first paired conductor PC-J1 and a second portion of the jack tine J-T3 is adjacent the second paired conductor PC-J2. Likewise, a first portion of the jack tine J-T6 is adjacent the second paired conductor PC-J2 and a second portion of the jack tine J-T6 is adjacent the first paired conductor PC-J1. In other words, any charge in the jack tines J-T3 and J-T6 is adjacent to a portion of each of the first and second paired conductors PC-J1 and PC-J2, thereby substantially negating the effect of the capacitive coupling between the split jack tines and the first and second paired conductors PC-J1 and PC-J2.
Further, by crossing the jack tines J-T3 and J-T6, the direction of the magnetic field formed between the first portions of the jack tines is opposite that of the magnetic field formed between the second portions, which substantially negates the inductive coupling between the split jack tines and the first and second paired conductors PC-J1 and PC-J2. In other words, mode conversion coupling is reduced by removing or subtracting away an equal amount of adverse coupling from each of the first and second paired conductors PC-J1 and PC-J2. A similar result may be obtained by crossing the jack tines J-T3 and J-T6 within the plug-jack interface portion of the communication plug.
Thus, a need exists for communication plugs and communication jacks configured to reduce cross-talk. A further need exists for a communication connector configured to reduce cross-talk caused by unwanted inter-modal coupling between the conducting elements of the connector. The present application provides these and other advantages as will be apparent from the following detailed description and accompanying figures.